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CompletedNCT04179136Updated Oct 27, 2023

The Role of Gut Microbiome on Cardiovascular Health Benefits of Dietary Lignans (CardioFlax Study).

An interventional study of lignan capsules contain 300 mg flaxseed (SDG) extract and Placebo treatment matching intervention in Healthy Volunteers, sponsored by King's College London. Completed at 1 site in United Kingdom. Open to female participants aged 20 Years to 70 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2023-10-27.

Sponsored by King's College London · Not applicable, Interventional, and Prevention

Phase
Not applicable
Study type
Interventional
Enrollment
45
Allocation
Randomized
Ages
20 Years to 70 Years
Sex
Female
01

Study summary

The aim of this study is to investigate the effects of gut microbial metabolism of flaxseed lignans on cardiovascular health. Enterolactone is the main gut microbial metabolite of lignans. The study population will be stratified in low and high enterolactone producers and will investigate whether high producers will have greater benefits than low producers, and whether low producers may become high producers after daily consumption of lignans over 8 weeks. The investigators will evaluate changes in endothelial function, blood pressure, arterial stiffness, insulin resistance, lipid profile and gut microbiome composition after 8 weeks daily consumption of flaxseed lignans.

Read the detailed description

Epidemiological studies have shown inverse relation between enterolactone levels and cardiovascular mortality. Participants will be stratified from first phase (NCT03573414) and then randomly allocated to treatment or placebo. Outcomes are measured at baseline and after 8 weeks post consumption.

02

Conditions studied

  • Healthy Volunteers

Keywords

  • Cardiovascular system Polyphenols
03

In context

Lead sponsor

King's College London is the lead sponsor of 506 studies on the registry; 125 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
20 Years to 70 Years
Sexes eligible
Female
Accepts healthy volunteers
Yes

Inclusion criteria

  • Healthy women aged 20-70 years
  • BMI between 18 and 35 kg/m2
  • Subjects are willing to maintain their normal eating/drinking habits and exercise habits to avoid changes in body weight over the duration of the study
  • Are able to understand the nature of the study
  • Able to give signed written informed consent
  • Signed informed consent form

Exclusion criteria

Exclusion Criteria:

  • Medical history of cardiovascular disease including coronary artery disease, cerebrovascular disease and peripheral artery disease
  • Hypertensive, as defined as SBP superior or equal to 140 mmHg, and CBP superior or equal to 90 mmHg
  • Participants with BMI superior to 35 kg/m2, and BMI below 18 kg/m2
  • Medical history of diabetes mellitus, metabolic syndrome, terminal renal failure or malignancies
  • Abnormal heart rhythm (lower or higher than 60-100 bmp)
  • Allergies to flaxseed or other significant food allergy
  • Subjects under medication that can affect the cardiovascular system or on vitamin/dietary supplements.
  • Subjects who have lost more than 10% of their weight in the past 6 months or are currently in a diet
  • Subjects who reported participant in another study within one month before the study start
  • Smoker Subjects
  • Pregnant women or planning to become pregnant in the next 6 months
  • Any reason or condition that in the judgment of the clinical investigator(s) may put the subject at unacceptable risk or that may preclude the subject from understanding or complying with the study's requirements.
05

Study design

Phase
Not applicable
Primary purpose
Prevention
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Quadruple (Participant, Care provider, Investigator, Outcomes assessor)
Enrollment
45 participants (actual)

Study arms

  • Active comparator
    High enterolactone producer's (intervention)

    lignan capsules contain 300 mg flaxseed (SDG) extract

    Dietary Supplement: lignan capsules contain 300 mg flaxseed (SDG) extract

  • Placebo comparator
    High enterolactone producer's (Control)

    Placebo treatment matching intervention

    Dietary Supplement: Placebo treatment matching intervention

  • Active comparator
    Low enterolactone producer's (intervention)

    lignan capsules contain 300 mg flaxseed (SDG) extract

    Dietary Supplement: lignan capsules contain 300 mg flaxseed (SDG) extract

  • Placebo comparator
    Low enterolactone producer's (Control)

    Placebo treatment matching intervention

    Dietary Supplement: Placebo treatment matching intervention

Interventions

  • Dietary supplementlignan capsules contain 300 mg flaxseed (SDG) extract

    lignan capsules contain 300 mg flaxseed (SDG) extract

  • Dietary supplementPlacebo treatment matching intervention

    Placebo treatment matching intervention

06

What researchers measure

Primary outcomes

  1. Change in flow-mediated dilation (FMD)

    To investigate the effect of daily consumption of 300 mg of flaxseed (SDG) extract vs Placebo for 8 weeks on endothelium-dependent flow mediated dilation (FMD) of the brachial artery (0, 8 weeks)

    Time frame: Baseline vs 8 weeks post-consumption

Secondary outcomes

  1. Change in flow-mediated dilation (FMD)

    To investigate the acute effect of 300 mg of flaxseed (SDG) extract vs Placebo on endothelium-dependent flow mediated dilation (FMD) of the brachial artery after 24- hour post-consumption.

    Time frame: Day 0, Day1 post-consumption

  2. Change in office blood pressure

    To investigate the effect of 300 mg flaxseed lignans (SDG) extract vs Placebo on peripheral systolic and diastolic blood pressure, and heart rate after 8 weeks daily consumption.

    Time frame: Day 0, Day 1 and 8 weeks post-consumption

  3. Change in pulse wave velocity (PWV)

    To determine the effect of 300 mg of lignans (SDG) vs Placebo on pulse wave velocity (PWV ) using a Sphygmocor device, after 8 weeks daily consumption

    Time frame: Baseline vs 8 weeks post-consumption

  4. Change in augmentation Index (AIx)

    To determine the effect of 300 mg of lignans (SDG) vs Placebo on augmentation index (PWA) using a Sphygmocor device, after 8 weeks daily consumption

    Time frame: Baseline vs 8 weeks post-consumption

  5. Change in Total cholesterol

    To investigate the effect of 300 mg Lignans (SDG) extract vs Placebo on blood lipids Total cholesterol after 8 weeks daily consumption

    Time frame: Baseline vs 8 weeks post-consumption

  6. Change in blood inflammatory markers (IL-6)

    To investigate the effect of 300 mg lignans (SDG) extract vs Placebo on inflammation markers (IL-6) after 8 weeks daily consumption.

    Time frame: Baseline vs 8 weeks post-consumption

  7. Change in glucose marker

    To investigate the effect of 300 mg lignans (SDG) extract vs Placebo on glucose levels (glucose) after 8 weeks daily consumption.

    Time frame: Baseline vs 8 weeks post-consumption

  8. Change in blood lipid (HDL cholesterol ) concentrations

    o investigate the effect of 300 mg Lignans (SDG) extract vs Placebo on blood lipids (HDL)after 8 weeks daily consumption

    Time frame: Baseline vs 8 weeks post-consumption

  9. Change in blood lipid (LDL cholesterol )concentrations

    o investigate the effect of 300 mg Lignans (SDG) extract vs Placebo on blood lipids( LDL cholesterol) after 8 weeks daily consumption

    Time frame: Baseline vs 8 weeks post-consumption

  10. Change in blood lipid (triglycerides) concentrations

    o investigate the effect of 300 mg Lignans (SDG) extract vs Placebo on blood lipids (triglycerides) after 8 weeks daily consumption

    Time frame: Baseline vs 8 weeks post-consumption

  11. Change in blood inflammatory markers (CRP)

    To investigate the effect of 300 mg lignans (SDG) extract vs Placebo on inflammation markers ( CRP) after 8 weeks daily consumption.

    Time frame: Baseline vs 8 weeks post-consumption

  12. Change in insulin markers

    To investigate the effect of 300 mg lignans (SDG) extract vs Placebo on glucose levels (insulin) after 8 weeks daily consumption.

    Time frame: Baseline vs 8 weeks post-consumption

  13. Change in glucose (HbA1c) markers

    To investigate the effect of 300 mg lignans (SDG) extract vs Placebo on glucose levels (HbA1c) after 8 weeks daily consumption.

    Time frame: Baseline vs 8 weeks post-consumption

Other outcomes

  1. Change in metabolic (poly)phenol metabolite concentrations

    To determine the plasma levels of polyphenol metabolites after acute and chronic consumption of flaxseed lignans (SDG).Measured by liquid chromotography-mass spectrometry (LC/MS)

    Time frame: Baseline, 24 hand 8 weeks post-consumption

  2. Change in metabolic (poly)phenol metabolite concentrations

    To determine the urine levels of polyphenol metabolites baseline and chronic consumption of flaxseed lignans (SDG). Measured by liquid chromotography-mass spectrometry (LC/MS)

    Time frame: Baseline vs 8 weeks post-consumption

  3. Gut microbiome composition

    To investigate changes in gut microbiota composition and diversity after 8 weeks consumption of flaxseed lignans (SDG) extract.

    Time frame: Baseline vs 8 weeks post-consumption

  4. Menopausal symptoms

    To investigate the effect of 300 mg flaxseed lignans (SDG) extract vs Placebo on menopausal symptoms using menopausal questionnaire for women over 45 years.

    Time frame: Baseline vs 8 weeks post-consumption

  5. Homeostatic model assessment

    To assess insulin resistance (IR) using homeostatic model assessment (HOMA).

    Time frame: Baseline vs 8 weeks post-consumption

07

Study locations

1 site
  • King's College London
    London, SE1 9NH, United Kingdom
08

References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Oct 27, 2023, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT04179136
Lead sponsor
King's College London
Responsible party
Sponsor
First posted
Nov 27, 2019
Start date
Nov 25, 2019
Primary completion
Jul 30, 2021
Completion
Jul 30, 2021
Last update
Oct 27, 2023

Study contacts

Dr.Ana Rodriguez-Mateos, PhD
principal investigator · King's College London

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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